Warpage control in microelectronic packages, and related assemblies and methods

ABSTRACT

A microelectronic device and/or microelectronic device package having a warpage control structure. The warpage control structure may be positioned over an encapsulating material, wherein the encapsulating material is positioned between the warpage control structure and a die positioned over a substrate. The warpage control structure may have a first thickness over a first portion of the encapsulating material and a second thickness over a second portion of the encapsulating material. Methods of forming the microelectronic device are also disclosed herein.

TECHNICAL FIELD

Embodiments of the disclosure relate to microelectronic devices.Specifically, some embodiments relate to warpage control in packagescomprising microelectronic devices and assemblies, and to relatedmethods.

BACKGROUND

During fabrication and testing, packaged microelectronic devices, forexample packaged semiconductor devices and assemblies, are subjected toa variety of stresses resulting at least from heating and cooling thesemiconductor devices and assemblies during assembly of the devices on asubstrate and encapsulation of the assembly, including application of anencapsulant (e.g., epoxy molding compound (EMC)), curing of the EMC,and/or reflow of external conductive elements (e.g., solder balls orbumps). These stresses may result in warpage of the semiconductordevice.

As a consequence of many factors, including demand for increasedportability, computing power, memory capacity and energy efficiency,microelectronic devices such as semiconductor devices and packagescomprising such devices, are continuously being reduced in size. Thesizes of the constituent features (i.e., critical dimensions) that formthe devices, e.g., circuit elements and interconnect lines, as well asthe pitch between (i.e., spacing) structures are also constantly beingdecreased to facilitate this size reduction.

Semiconductor devices may be stacked, such as, in package on package(POP) assemblies to increase one or more of a capacity, computing power,etc. of the resulting semiconductor device while still consuming lessreal estate (i.e., surface area) and facilitating signal speed andintegrity. However, packages comprising stacked semiconductor devicesmay result in enhanced sensitivity to warpage of the package.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a semiconductor device packageaccording to an embodiment of the present disclosure;

FIGS. 2A, 2B, and 2C are side views of a semiconductor device packageaccording to an embodiment of the present disclosure;

FIGS. 3A and 3B are cross-sectional side views of a semiconductor devicepackage according to an embodiment of the present disclosure;

FIG. 4 is a cross-sectional side view of a semiconductor device packageaccording to an embodiment of the present disclosure;

FIG. 5 is a graphical representation of a reflow process according to anembodiment of the present disclosure;

FIG. 6A is a side view of a semiconductor device package according to anembodiment of the present disclosure;

FIG. 6B is a top view of an embodiment of the semiconductor devicepackage of FIG. 6A according to an embodiment of the present disclosure;

FIG. 7A is a side view of a semiconductor device package according to anembodiment of the present disclosure;

FIG. 7B is a top view of an embodiment of the semiconductor devicepackage of FIG. 7A according to an embodiment of the present disclosure;

FIG. 8A is a side view of a semiconductor device package according to anembodiment of the present disclosure;

FIG. 8B is a top view of an embodiment of the semiconductor devicepackage of FIG. 8A according to an embodiment of the present disclosure;

FIG. 9A is a side view of a semiconductor device package according to anembodiment of the present disclosure;

FIG. 9B is a top view of implementation of the semiconductor devicepackage of FIG. 9A according to an embodiment of the present disclosure;

FIG. 9C is a top view of implementation of the semiconductor devicepackage of FIG. 9A according to an embodiment of the present disclosure;

FIG. 10A is a side view of a semiconductor device package according toan embodiment of the present disclosure;

FIG. 10B is a top view of an implementation of the semiconductor devicepackage of FIG. 10A according to an embodiment of the presentdisclosure;

FIG. 11 is a side view of a semiconductor device package according to anembodiment of the present disclosure;

FIG. 12 is a side view of a semiconductor device package according to anembodiment of the present disclosure;

FIG. 13 is a flowchart of an example method of forming a semiconductordevice according to an embodiment of the present disclosure; and

FIG. 14 is a flowchart of an example method of forming a package onpackage (POP) stack according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

The illustrations presented herein are not meant to be actual views ofany particular semiconductor device or component thereof, but are merelyidealized representations employed to describe illustrative embodiments.The drawings are not necessarily to scale.

As used herein, relational terms, such as “first,” “second,” “top,”“bottom,” etc., are generally used for clarity and convenience inunderstanding the disclosure and accompanying drawings and do notconnote or depend on any specific preference, orientation, or order,except where the context clearly indicates otherwise.

As used herein, the term “and/or” means and includes any and allcombinations of one or more of the associated listed items.

As used herein, the term “substantially” or “about” in reference to agiven parameter means and includes to a degree that one skilled in theart would understand that the given parameter, property, or condition ismet with a small degree of variance, such as within acceptablemanufacturing tolerances. For example, a parameter that is substantiallymet may be at least about 90% met, at least about 95% met, at leastabout 99% met, or even 100% met.

As used herein, the term “device” or “memory device” may include adevice with memory, but is not limited to a device with only memory. Forexample, a device or a memory device may include memory, a processor,and/or other components or functions. For example, a device or memorydevice may include a system on a chip (SOC). In some embodiments, thecomputation methods described herein may be applicable to storagedevice, such as solid-state drives. Therefore, the term “memory device”used herein may be include a storage device.

FIG. 1 illustrates a cross-sectional side view of a microelectronicdevice package in the form of semiconductor device package 100. Thesemiconductor device package 100 may include one or more semiconductordice 102 disposed within an encapsulant, such as a mold material 104,for example, an EMC. As shown, the semiconductor dice 102 may beinverted in a “flip chip” orientation mechanically and electricallyconnected to a substrate in the form of an interposer layer 110 throughone or more conductive elements 106 (e.g., solder bumps, solder balls,micro-bumps, etc.). In other conventional microelectronic devicepackages, the semiconductor dice may be secured to an interposer bytheir back aides, and electrically connected to the interposer with wirebonds extending from the active surface to conductive pads of theinterposer. The interposer layer 110 may be mechanically andelectrically coupled to a package substrate 130 through one or moreother conductive elements in the form of solder bumps 112 connected toconductive contact pads 132 of package substrate 130. The contact pads132 may provide an electrical connection between the interposer layer110 and the package substrate 130 through the one or more solder bumps112. The package substrate 130 may comprise an organic material (e.g.,printed circuit board) or an inorganic material (e.g., silicon orceramic). Alternatively, for example in wafer-level or panel-levelpackages, a redistribution layer (RDL) comprising one or more levels ofconductive traces carried by dielectric material may serve as asubstrate.

The interposer layer 110 may include one or more alternating conductiveand insulating (i.e., dielectric) layers. For example, the interposerlayer 110 may include a first patterned conductive layer 114 comprisinga conductive material extending through a dielectric material disposedover a second patterned conductive layer 116 comprising a conductivematerial extending through a dielectric material disposed over a thirdpatterned conductive layer 118 comprising a conductive materialextending through a dielectric material. Each patterned conductive layer114, 116, and 118 may include conductive portions 120 separated byinsulating portions 122. The patterned conductive layers 114, 116, and118 may further include a dielectric layer 124, such as an interlayerdielectric layer or an inter-metal dielectric layer formed on and/or inthe conductive portions 120 of the respective patterned conductive layer114, 116, and 118.

Warpage may occur within the semiconductor device package 100 for avariety of reasons and at different times during the process offabricating the semiconductor device package 100. For example, warpagemay occur during a reflow process, such as the reflow process used toattach the interposer layer 110 to the package substrate 130. In someembodiments, an encapsulation process may cause warpage of theinterposer layer 110. For example, curing the mold material 104, maycause the mold material 104 to shrink more than other materials of theinterposer layer 110 and or semiconductor dice 102 causing thesemiconductor device package 100 to warp. In some embodiments, otherprocesses, such as forming under bump metallization (UBM), baking, etc.may cause the semiconductor device package 100 to warp. Generally,warpage of the semiconductor device package 100 is a result of adiffering coefficient of thermal expansion (CTE) between the materialsused to form the different portions of the semiconductor device package100. As the semiconductor device package 100 experiences significanttemperature changes throughout the forming process the differing CTEsmay cause the semiconductor device package 100 to warp or bend as someportions of the semiconductor device package 100 expand or contract atgreater rates than other portions of the semiconductor device package100 responsive to temperature changes.

FIGS. 2A, 2B, and 2C illustrate different types of warpage that may beexperienced by a semiconductor device package 100. As noted above apackage substrate may comprise an organic material (e.g., printedcircuit board) or an inorganic material (e.g., silicon or ceramic). Inother embodiments, for example in wafer-level or panel-level packages, aredistribution layer (RDL) comprising one or more levels of conductivetraces carried by dielectric material may serve as a substrate. Therelative mechanical strength and coefficient of thermal expansion of thesubstrate materials may affect the nature and degree of the warpagetendencies of the semiconductor device package 100.

FIG. 2A illustrates a substrate in the form of an interposer layer 110with concave or negative warpage or simple bending (e.g., smile). Thenegative warpage may cause outer ends 202 of the interposer layer 110 tobe positioned a greater distance from the package substrate 130 than acenter portion 204 of the interposer layer 110 when the packagesubstrate 130 is substantially planar. The greater distance at the outerend 202 of the interposer layer 110 may cause the solder bumps 112 toseparate from the contact pads 132 near the outer ends 202. Suchseparation may cause the semiconductor device package 100 to fail due toa loss of electrical connection or a weak connection. For example, insome embodiments, the semiconductor device package 100 may fail duringtesting or the semiconductor device package 100 may fail earlier thanexpected (e.g., before completing its expected lifecycle) due tocyclical temperature changes during operation. In some embodiments, thepackage substrate 130 may also include warpage. For example, the packagesubstrate 130 may experience similar negative warpage increasing thedistance between the outer ends 202 of the interposer layer 110. Inanother example, the package substrate 130 may experience positivewarpage such that the distance between the outer end 202 of theinterposer layer 110 and the package substrate 130 may be reduced.

FIG. 2B illustrates a substrate in the form of an interposer layer 110with positive or convex warpage or simple bending (e.g., frown/cry). Thepositive warpage may cause the center portion 204 of the interposerlayer 110 to be positioned a greater distance from the package substrate130 than the outer ends 202 of the interposer layer 110 when the packagesubstrate 130 is substantially planar. In some embodiments, the packagesubstrate 130 may not be substantially planar. For example, the packagesubstrate 130 may experience similar positive warpage causing thedistance between the center portion 204 of the interposer layer 110 andthe package substrate 130 to increase. In some embodiments, the packagesubstrate 130 may experience negative warpage similar to that describedabove with respect to FIG. 2A. The distance between the packagesubstrate 130 and the center portion 204 of the interposer layer 110 maysimilarly decrease for a package substrate 130 with positive warpage. Asdescribed above, as the distance between the interposer layer 110 andthe package substrate 130 increases in different regions thesemiconductor device package 100 may fail due to a loss of connection ora weak connection.

In some embodiments, the substrate configured as an interposer layer 110may experience different types of warpage in different regions asillustrated in FIG. 2C. For example, a first outer end 202 a mayexperience negative warpage while a second outer end 202 b mayexperience positive warpage. In addition, compound warpage may occur indifferent directions along the major plane of interposer layer 110. Thecombinations of different varieties of warpage may cause the interposerlayer 110 to experience more complex warpage, such as twist, saddle,etc.

The warpage of the interposer layer 110 may be predicted and degree ofwarpage estimated from material properties of the different componentsof the semiconductor device package 100 and known environmentalconditions from the forming process. For example, finite elementanalysis (FEA) software may be used to model the semiconductor devicepackage 100 and simulate the process of forming the semiconductor devicepackage 100 by modelling the expected stresses and resulting warpage ofthe semiconductor device package 100. The semiconductor device package100 may include, for example, one or more memory devices, a combinationof different types of semiconductor devices, a package on packageassembly of multiple semiconductor devices, etc.

Some embodiments of the present disclosure may include a microelectronicdevice package. The microelectronic device package may include asubstrate. The microelectronic device package may further include one ormore microelectronic devices positioned over the substrate. Themicroelectronic device package may also include an encapsulant materialsurrounding and extending over the one or more microelectronic devices.The microelectronic device package may further include at least onewarpage control layer of non-uniform thickness positioned over andsecured to a surface of the encapsulant material.

FIG. 3A illustrates a semiconductor device package 300. Thesemiconductor device package 300 may include one or more semiconductordice 302 encapsulated in, for example, an EMC 304. The EMC 304 mayencompass the one or more semiconductor dice 302 covering at least threesides of the one or more semiconductor dice 302, and extend over the oneor more semiconductor dice 302. The semiconductor dice 302 and the EMC304 may be positioned on an interposer layer 310. The semiconductordevice package 300 may include a warpage control structure in the formof warpage control layer 306 positioned over the EMC 304 to controlwarpage of the semiconductor device package 300. For example, thewarpage control layer 306 may be configured to substantially preventwarpage of the semiconductor device package 300 in one or moreanticipated directions. In some embodiments, the warpage control layer306 may be configured to reduce warpage of the semiconductor devicepackage 300 to an acceptable degree.

In some embodiments, the EMC 304 may cover side portions of thesemiconductor dice 302, while a top portion of the semiconductor dice302 may remain free from the EMC 304. An insulating layer, such as adielectric material may be positioned between the top semiconductor die302 and the warpage control layer 306, such that the warpage controllayer 306 is positioned directly over the insulating layer.

FIG. 3B illustrates the neutral axes 308, 309 of the semiconductordevice package 300 before and after application of the warpage controllayer 306. The first neutral axis 308 may represent the neutral axis ofthe semiconductor device package 300 before the warpage control layer306 is applied. The addition of the warpage control layer 306 may resultin the neutral axis moving toward the warpage control layer 306 to thesecond neutral axis 309. Movement of the position of the first neutralaxis 308 upwardly to the position of the second neutral axis 309 maystrengthen the semiconductor device package 300 and enhance the abilityof the semiconductor device package 300 to resist bending or handlingstresses in the die during manufacturing, for example, strengthening theoverall package. In some embodiments, movement of the first neutral axis308 to the second position of the neutral axis 309 may move bendingstresses away from more sensitive (e.g., fragile, weak) components ofthe semiconductor device package 300, such as the semiconductor dice 302and into less sensitive (e.g., stronger, robust) components of thesemiconductor device package 300, such as the EMC 304.

The warpage control layer 306 may be formed from a material having acoefficient of thermal expansion that is higher or lower than theaverage coefficient of thermal expansion of the semiconductor devicepackage 300 to substantially reduce the warpage of the semiconductordevice package 300. For example, the warpage control layer 306 may beformed from a material that has high strength and a high coefficient ofthermal expansion at the temperatures present during the formingprocess. Such an approach may balance warpage tendency induced by therelatively high coefficient of thermal expansion of the interposer layer310 relative to the low coefficient of thermal expansion of the siliconof semiconductor dice 302. In some embodiments, the warpage controllayer 306 may be formed from a metal (e.g., titanium, gold, tungsten,silicon, copper, aluminum, etc.), a polymer (e.g., polybenzoxazole,polyimide, polyamide, benzocyclobutene, etc.), a composite (e.g.,prepreg, carbon fiber, fiber glass, etc.), and/or a ceramic (e.g.,alumina, yttrium oxide, aluminum nitride, aluminum oxide, siliconcarbide, pyrolitic boron nitride, etc.).

In some embodiments, a semiconductor package may be stacked on anothersemiconductor package. Such package on package (POP) stacks, as notedabove, may reduce the real estate consumed by a package while enhancingelectrical properties, such as signal speed and integrity. For example,a memory device may include a POP stack configured to increase thecapacity of the memory device while enabling the memory device to beattached to a processor in a location sized for a smaller capacitymemory device.

FIG. 4 illustrates an embodiment of a POP stack 400. The POP stack 400may include a first semiconductor device package 410 and a secondsemiconductor device package 420. The first semiconductor device package410 may include one or more semiconductor dice 412 encapsulated in anEMC 414. The one or more semiconductor dice 412 and EMC 414 may bepositioned over a substrate in the form of an interposer layer 416. Theinterposer layer 416 may be coupled to a package substrate 418. Thesecond semiconductor device package 420 may be positioned over the firstsemiconductor device package 410. The second semiconductor devicepackage 420 may include one or more semiconductor dice 422 encapsulatedin an EMC 424. The one or more semiconductor dice 422 and EMC 424 may bepositioned over another substrate in the form of an interposer layer426. The interposer layer 426 may be coupled to a package substrate 428.The second semiconductor device package 420 may be coupled to the firstsemiconductor device package 410 through an electrical connection 430.The electrical connection 430 may include solder bumps, pins, vias,wires, etc. The first semiconductor device package 410 may include POPconnections 432 configured to connect the POP stack to anotherelectronic device, such as another semiconductor device package, devicemother board, etc.

In some embodiments, one or more additional semiconductor devicepackages may be positioned (e.g., stacked, coupled, etc.) above and/orbelow the first and second semiconductor device packages 410, 420.

In some embodiments, the first semiconductor device package 410 mayinclude one or more of different circuitry, different materialproperties, a different configuration, or all of the foregoing, than thesecond semiconductor device package 420. The differences between thefirst semiconductor device package 410 and the second semiconductordevice package 420 may cause the initiation, degree, direction, or allof warpage of the first semiconductor device package 410 and the warpageof the second semiconductor device package 420 to be different.Different warpage configurations and degrees may result in weak and/orbroken connections between the first and second semiconductor devicepackages 410, 420.

In some embodiments, a warpage control layer may be used to controlwarpage on one or more of the first semiconductor device package 410 andthe second semiconductor device package 420. For example, a warpagecontrol layer may be used on one or both of the first semiconductordevice package 410 and the second semiconductor device package 420 andbe configured to substantially prevent warpage on each of thesemiconductor device packages 410, 420. In some embodiments, a warpagecontrol layer on the second semiconductor device package 420 may beconfigured to modify, control, or both, of a warpage of the secondsemiconductor device package 420 such that the warpage of the secondsemiconductor device package 420 is substantially the same as (e.g.,complementary to) the warpage of the first semiconductor device package410.

FIG. 5 is a graphical representation of the warpage of a semiconductordevice package during a reflow process. A reflow process may be used toform conductive elements in the form of solder joints (e.g., solderbumps) in the semiconductor device package and/or between multiplesemiconductor device packages, such as in a POP stack. The magnitude ofthe warpage at different temperatures is illustrated along a temperaturescale 502 representing the temperature cycle of a reflow process.

The temperature during a reflow process may begin at room temperature504. The temperature of the semiconductor device may be slowly raisedduring a preheat phase to bring the semiconductor device to a thermalsoak temperature. A thermal soak temperature may be between about 130degrees Celsius and about 180 degrees Celsius. The thermal soak zone isrepresented in region 510. The semiconductor device package may bemaintained at the thermal soak temperature for between about 30 secondsand about 240 seconds. The thermal soak may remove volatiles from thesolder paste to be formed into bumps from the semiconductor devicepackage and activate fluxes on the semiconductor device. After thethermal soak zone the temperature of the semiconductor device packagemay be raised above the liquidus temperature of the solder. Differenttypes of solder may have different liquidus temperatures. In someembodiments, the solder may have a liquidus temperature of between about180 degrees Celsius and about 220 degrees Celsius. The reflow zone 512(e.g., time above reflow, time above liquidus (TAL)) generally lastsbetween about 20 seconds and about 120 seconds. The maximum acceptabletarget temperature in the reflow zone 512 may be determined from thecomponent in the semiconductor device with the lowest tolerance for hightemperatures. (e.g., the component most susceptible to thermal damage ordegradation). The maximum acceptable target temperature may be betweenabout 220 degrees Celsius and about 260 degrees Celsius. After thetemperature of the semiconductor device package drops below the liquidustemperature the semiconductor device package may be slowly cooled duringa cool down phase 514 bringing the temperature of the semiconductordevice package back to room temperature 504.

Referring to FIG. 5, a first semiconductor device package 520 mayexperience large amounts of warpage through the reflow process. Awarpage control structure in the form of a warpage control layer may beapplied to the first semiconductor device package 520 to form a warpagecontrolled semiconductor device package 522 that may experience lesswarpage throughout the reflow process and subsequent operation of thepackage. In some embodiments, the warpage control layer may beconfigured to match the warpage of the controlled semiconductor devicepackage 522 to a control warpage 524 (e.g., guide warpage, guidelinewarpage, etc.). In some embodiments, the control warpage 524 mayrepresent warpage of a semiconductor device package to which thecontrolled semiconductor device package 522 may be coupled (e.g.,adjoined, attached, connected to, etc.), such as in a POP stack. Forexample, the control warpage 524 may represent the base semiconductordevice package in a POP stack. In some embodiments, the control warpage524 may represent the warpage of a POP stack to which the controlledsemiconductor device package 522 will be coupled. As the number ofsemiconductor device packages in a POP stack increase, the warpage ofthe POP stack may decrease.

In some embodiments, the control warpage 524 may be determined from amodel of the semiconductor device package (e.g., base semiconductordevice, POP stack, base semiconductor package, etc.). The model of thesemiconductor device package may be the result of mathematical models,computer simulations, etc. In some embodiments, the model of thesemiconductor device package may be developed from empirical data, suchas historical data from similar semiconductor device packages. In someembodiments, the model may be developed through a combination ofempirical and mathematical models.

Some embodiments of the present disclosure may include a controlledwarpage microelectronic device package. The controlled warpagemicroelectronic device package may include at least one microelectronicdevice substantially encapsulated in a molding material. The controlledwarpage microelectronic device package may further include a warpagecontrol structure secured to the molding material. The warpage controlstructure may include a first material having a non-uniform thickness. Afirst portion of the first material may have a first thickness. At leasta second portion of the first material may have a second thickness. Thefirst portion may be positioned over a first region of the moldingmaterial and the second portion may be positioned over a second regionof the molding material.

FIGS. 6A and 6B illustrate an embodiment of a warpage controlledsemiconductor device package 600. A semiconductor device package 602 mayhave a warpage control structure in the form of warpage control layer604 disposed over the semiconductor device package 602 to form thewarpage controlled semiconductor device package 600. The warpage controllayer 604 may be configured to control the warpage of the semiconductordevice package 602. For example, the warpage control layer 604 may beconfigured to substantially prevent warpage of the semiconductor devicepackage 602 in at least some regions of the semiconductor device package602. In some embodiments, the warpage control layer 604 may beconfigured to increase an amount of warpage in the semiconductor devicepackage 602 in at least some regions of the semiconductor device package602. In some embodiments, the warpage control layer 604 may beconfigured to reverse the warpage (e.g., change the warpage frompositive warpage to negative warpage) of the semiconductor devicepackage 602 in at least some regions of the semiconductor device.

The warpage control layer 604 may control the warpage of thesemiconductor device package 602 with a selected thickness of thewarpage control layer 604, wherein the selected thickness of the warpagecontrol layer 604 is the distance between a top surface 601 of thesemiconductor device package 602 and a top surface 603 of the warpagecontrol layer 604. For example, regions of the semiconductor devicepackage 602 positioned under and/or near a thick region 606 of thewarpage control layer 604 may be more susceptible to warpage and, thus,require greater control. Regions of the semiconductor device package 602under and/or near a thin region 608 of the warpage control layer 604 maybe less susceptible to warpage and, so may require little or no control.In some embodiments, thick regions 606 of the warpage control layer 604may be positioned over regions of the semiconductor device package 602that are more susceptible to warpage to provide even warpage across thesemiconductor device package 602. In some embodiments, thin regions 608of the warpage control layer 604 may be positioned over a region of thesemiconductor device package 602 where additional warpage is necessaryto match a desired amount of warpage.

FIGS. 6A and 6B illustrate, respectively, a side view and top view of awarpage controlled semiconductor device package 600 having a thickregion 606 of the warpage control layer 604 in the form of at least oneframe structure which may extend, as shown, around a perimeter of thewarpage control layer 604 proximate peripheral edges of semiconductordevice package 602. However, the warpage control layer, and specificallythick region may comprise, for example, multiple frame structures,either separate or connected in a grid pattern of rows and columns, in apattern of honeycomb (i.e., hexagonal) shaped mutually adjacent frames.The thick region 606 may define a recess 610 in a central region of thewarpage control layer 604 in the thin region 608 of the warpage controllayer 604. The thickness of various regions of the warpage control layer604 may range between 0 μm and about 0.5 millimeters (mm), such asbetween about 0 μm and about 20 μm, or between about 2 μm and about 10μm. For example, the thick region 606 of the warpage control layer 604may have a thickness of up to about 20 μm and the thin region 608 of thewarpage control layer 604 may have a thickness of as little as 0 μm(i.e., be omitted entirely). In implementing warpage control layers inother types of packaging, for example in power electronic devicepackaging employing ceramic substrates, the warpage control layer may befar thicker, for example about 5 mm to about 10 mm, to counteractwarpage tendencies otherwise induced by the substrate material. In someembodiments, the thickness of thick region 606 may be non-uniform (e.g.,different regions of the thick region 606 may have differentthicknesses). In some embodiments, the thickness of the thin region 608may be non-uniform.

FIGS. 7A and 7B illustrate a side view and top view of another warpagecontrolled semiconductor device package 600′. The warpage control layer604 may gradually transition from the thick region 606 to the thinregion 608 in a transition region 710. For example, the transitionregion 710 may define a linear transition between the thick region 606and the thin region 608, as illustrated in FIG. 7A. In some embodiments,the transition region 710 may define a profile having a curved shape(e.g., circular, parabolic, exponential, etc.). In some embodiments, thetransition region 710 may be a more abrupt transition, such as multiplesteps, chamfers, rounded edges, etc.

In some embodiments, the thick region 606 may extend around a perimeterof the warpage control layer 604 and the thin region 608 may be locatedin a center region of the warpage control layer 604. The lineartransition between the thick region 606 and the thin region 608 maydefine a recess in the shape of an inverted pyramid. In someembodiments, the thick region 606 may extend along parallel sides of thewarpage control layer 604 and the thin region 608 may be located in acenter region of the warpage control layer 604, such that a transitionbetween the thick region 606 and the thin region 608 may define achannel through the warpage control layer 604 that is substantiallyparallel with the thick regions 606 along the parallel sides of thewarpage control layer 604.

FIGS. 8A and 8B illustrate a side view and top view of a further warpagecontrolled semiconductor device package 600″. The warpage control layer604 may include one or more thick regions 606 and one or more thinregions 608. The one or more thick regions 606 may form ridges in thewarpage control layer 604. In some embodiments, an outer ridge 812 maysurround a recess 814 defined between the outer ridge 812 and an innerridge 816. In some embodiments, the thick regions 606 may have differentthicknesses. For example, the outer ridge 812 may have a first thicknessand the inner ridge 816 may have a second thickness. In someembodiments, the outer ridges 812 may have a thickness that is greaterthan the thickness of the inner ridge 816. In other embodiments, thethickness of the outer ridges 812 may be less than the thickness of theinner ridge 816.

The one or more thin regions 608 may include an outer region 818extending between the outer ridge 812 and the perimeter of the warpagecontrol layer 604. In some embodiments, the recess 814 and the outerregion 818 of the one or more thin regions 608 may have substantiallythe same thickness. In some embodiments, the recess 814 and the outerregion 818 of the one or more thin regions 608 may have differentthicknesses. In some embodiments, one or more of the recess 814 and theouter region 818 may be substantially free of material of the warpagecontrol layer 604. In some embodiments, the thickness of at least one ofthe recess 814 and the outer region 818 may be non-uniform.

In some embodiments, the one or more thick regions 606 and the one ormore thin regions 608 may form a pattern, such as a grid pattern orhoneycomb pattern. In some embodiments, the one or more thin regions 608may be substantially free from warpage control material such that thewarpage control layer 604 is substantially a pattern of ridges formed bythe one or thick regions 606.

FIGS. 9A, 9B, and 9C illustrate embodiments of yet another warpagecontrolled semiconductor device package 600′″. The warpage control layer604 may include one or more thick regions 606 and one or more thinregions 608. In some embodiments the thick region 606 may form a ridge,configured for example as a mesa, in a center portion of the warpagecontrol layer 604. The thin region 608 may extend from the thick region606 to at least one perimeter side of the warpage control layer 604. Insome embodiments, thin region 608 may be substantially free of materialof the warpage control layer 604. In some embodiments, the thickness ofthin region 608 may be non-uniform.

In some embodiments, the thick region 606 may be non-uniform. Forexample, the thick region 606 may gradually transition from a firstthickness near a first transition point 910 between the thick region 606and the thin region 608 to a second thickness in an area near the centerof the thick region 606. In some embodiments, the second thickness maybe larger than the first thickness. In some embodiments, the firstthickness may be larger than the second thickness. In some embodiments,the thick region 606 may have a third thickness at a second transitionpoint 912 between the thick region 606 and the thin region 608. Thethickness of the thick region 606 may gradually transition between thefirst thickness and the third thickness.

FIG. 9B illustrates a top view of one implementation of the warpagecontrolled semiconductor device package 600′″ illustrated in FIG. 9A.The thick region 606 may form a ridge in a central region of the warpagecontrol layer 604. The thin region 608 may surround the thick region 606extending from the thick region 606 to the perimeter of the warpagecontrol layer 604.

FIG. 9C illustrates a top view of another implementation of the warpagecontrolled semiconductor device package 600′″ illustrated in FIG. 9A.The thick region 606 may form a ridge in a central region of the warpagecontrol layer 604. The ridge may extend from a first side 914 of thewarpage control layer 604 to a second side 916 of the warpage controllayer 604. The thin region 608 may similarly extend from the first side914 to the second side 916 of the warpage control layer 604substantially parallel to the ridge of the thick region 606. Similarly,the embodiments of FIGS. 6A-8A may form respective ridges and channelsextending from the first side 914 to the second side 916 of therespective warpage control layers 604.

Some embodiments of the present disclosure may include a microelectronicdevice package. The microelectronic device package may include one ormore microelectronic devices connected to a substrate. Themicroelectronic device package may further include an encapsulantmaterial extending around and over the one or more microelectronicdevices and abutting a surface of the substrate. The microelectronicdevice package may also include at least two warpage control structuressecured to a surface of the encapsulant material and extending over theone or more microelectronic devices.

FIGS. 10A and 10B illustrate, respectively, a side view and top view ofa still further warpage controlled semiconductor device package 600″″.In some embodiments, the one or more warpage control layers 1004 a, 1004b may be positioned over the semiconductor device package 602. The oneor more warpage control layers 1004 a, 1004 b, may include one or morethick regions 606 and one or more thin regions 608. For example, a firstwarpage control layer 1004 a and a second warpage control layer 1004 bmay be positioned adjacent to one another over the semiconductor devicepackage 602. The first warpage control layer 1004 a may include one ormore thick regions 606 forming ridges and one or more thin regions 608forming channels. Similarly, the second warpage control layer 1004 b mayinclude one or more thick regions 606 forming ridges and one or morethin regions 608 forming channels.

In some embodiments, the first warpage control layer 1004 a and thesecond warpage control layer 1004 b may be formed from differentmaterials. For example, the first warpage control layer 1004 a may beformed from a first material and the second warpage control layer 1004 bmay be formed from a second material. In some embodiments, at least oneof the first material and the second material may be configured tosubstantially prevent warpage. For example, the material may have a lowcoefficient of thermal expansion at the reflow temperatures. In someembodiments, at least one of the first material and the second materialmay be configured to encourage warpage. For example, the material mayhave a high coefficient of thermal expansion at the reflow temperatures.For example, the warpage control layers 1004 a, 1004 b may be formedfrom a metal (e.g., titanium, gold, tungsten, silicon, copper, aluminum,etc.), a polymer (e.g., polybenzoxazole, polyimide, polyamide,benzocyclobutene, etc.), a composite (e.g., prepreg, carbon fiber, fiberglass, etc.), and/or a ceramic (e.g., alumina, yttrium oxide, aluminumnitride, aluminum oxide, silicon carbide, pyrolitic boron nitride,etc.).

With different materials the thick regions 606 and thin regions 608 mayhave differing effects on the warpage of the semiconductor devicepackage 602. For example, if the warpage control layer 1004 a, 1004 b isformed from a material configured to substantially prevent warpage thethick regions 606 may provide greater resistance to warpage than thethin regions 608. However, if the warpage control layer 1004 a, 1004 bis formed from a material configured to encourage warpage the thickregions 606 may generate greater amounts of warpage than the thinregions 608.

FIG. 11 illustrates a side view of a warpage controlled semiconductordevice package 600 v. In some embodiments, the second warpage controllayer 1004 b may be positioned over at least a portion of the firstwarpage control layer 1004 a. For example, the first warpage controllayer 1004 a may be formed with a thick region 606 in a central regionof the first warpage control layer 1004 a and a thin region 608surrounding the thick region 606, similar to the embodiment of thewarpage controlled semiconductor device package 600“ ” illustrated inFIGS. 9A-9C. The second warpage control layer 1004 b may be formed overthe thin regions 608 also surrounding the thick region 606 of the firstwarpage control layer 1004 a.

FIG. 12 illustrates a side view of a warpage controlled semiconductordevice package 600 vi. In some embodiments, the second warpage controllayer 1004 b may be positioned over at least a portion of the firstwarpage control layer 1004 a. In another example, the first warpagecontrol layer 1004 a may be formed with the thin region 608 in a centralregion of the first warpage control layer 1004 a and the thick region606 surrounding the thin region 608 forming a channel and/or recess inthe first warpage control layer 1004 a, similar to the embodiment of thewarpage controlled semiconductor device package 600 illustrated in FIGS.6A and 6B. The second warpage control layer 1004 b may be formed overthe thin regions 608 within the recess and/or channel between the thickregions 606 of the first warpage control layer 1004 a.

The shape and/or material of the warpage control layers 604, 1004 a,1004 b may be selected to control the warpage of the semiconductordevice package 600, such as substantially preventing warpage of thesemiconductor device package 600 or controlling warpage of thesemiconductor device package 600 to match a control warpage, such as thewarpage of a base semiconductor device package, POP stack, etc. Theshapes materials, or both, of the warpage control layers 604, 1004 a,and 1004 b may be designed through a model of the warpage controlledsemiconductor device package 600. The model of the warpage controlledsemiconductor device package 600, 600′, 600″, 600′″, 600″″, 600 v, 600vi may be the result of mathematical models, computer simulations (e.g.,finite element analysis software), etc. In some embodiments, the modelof the warpage controlled semiconductor device package 600 may bedeveloped from experimental data. In some embodiments, the model may bedeveloped through a combination of experimental and mathematical models.

Some embodiments of the present disclosure may include a method offorming a device package. The method may include positioning at leastone die on a substrate. The method may also include encapsulating the atleast one die in a molding compound extending to a surface of thesubstrate. The method may further include curing the molding compound.The method may also include applying at least two warpage controlstructures over the molding compound.

FIG. 13 is a flow chart representing a method of forming a warpagecontrolled semiconductor device 1300. Also referring to FIGS. 3A-12.Semiconductor devices are generally formed at a wafer or strip levelwith multiple semiconductor devices being formed on a single wafer orstrip and then separated through a cutting or dicing process after thesemiconductor devices are formed.

A substrate in the form of, for example, an interposer layer 310 may beformed on a wafer or strip in act 1302. As described above theinterposer layer 310 may include one or more patterned conductive layersand may include differing patterns of conductive portions and insulatingportions. The interposer layer 310 may be formed through a process suchas photolithography, etching (e.g., wet etching, dry etching, photoetching, atomic layer etching, etc.), deposition (e.g., chemical vapordeposition, atomic layer deposition, physical vapor deposition etc.),and other conventional processes.

One or more semiconductor dice 302 may be positioned on the interposerlayer 310 in act 1304. In some embodiments, the warpage controlledsemiconductor device package may only include a single semiconductor die302. In some embodiments, the warpage controlled semiconductor devicemay include more than one semiconductor die 302. For example, thesemiconductor dice 302 may be stacked one on top of the other. In someembodiments, the semiconductor dice 302 may be positioned adjacent toone another, wherein both semiconductor dice 302 are in contact with theinterposer layer 310. The one or more semiconductor dice 302 may includesolder bumps configured to form an electrical connection between the oneor more semiconductor dice 302 and the interposer layer 310.

Once the semiconductor dice 302 are positioned on the interposer layer310 in act 1304, the semiconductor dice 302 may be encapsulated with amolding compound in act 1306. The molding compound may be configured toprotect and secure the one or more semiconductor dice 302 in positionrelative to the interposer layer 310. The molding compound may cover theside surfaces and top surface of the one or more semiconductor dice 302such that all portions of the one or more semiconductor dice 302 arecovered by the molding compound (e.g., no portion of the one or moresemiconductor dice 302 is exposed to an area outside the moldingcompound).

The molding compound may then be cured in act 1308. The molding compoundmay harden during the curing process securing the one or moresemiconductor dice 302 to the interposer layer 310 and forming aprotective layer around the one or more semiconductor dice 302 and theinterposer layer 310.

After the molding compound is cured in act 1308, the warpage controllayer 306 may be applied to a top surface of the molding compound in act1310. The warpage control layer 306 may be applied through a similarprocess to the interposer layer such as photolithography, etching (e.g.,wet etching, dry etching, photo etching, atomic layer etching, etc.),deposition (e.g., chemical vapor deposition, atomic layer deposition,physical vapor deposition etc.), electroplating, etc. Further, thewarpage control layer may comprise a preformed structure, and adhered tothe semiconductor package.

In some embodiments, the warpage control layer 306 may include a firstwarpage control layer 1004 a and a second warpage control layer 1004 b.The first and second warpage control layers 1004 a, 1004 b may beapplied or formed in two separate acts. For example, the first warpagecontrol layer 1004 a may be applied or formed in a first process act andthe second warpage control layer 1004 b may be applied or formed afterthe first warpage control layer 1004 a in a second process act. In someembodiments, the first process act and the second process act may bedifferent processes. For example, the first warpage control layer 1004 amay be applied with a first process act such as chemical vapordeposition. The second warpage control layer 1004 b may then be appliedthrough a second process step, such as electroplating.

In some embodiments, the first warpage control layer 1004 a and thesecond warpage control layer 1004 b may be formed from differentmaterials. The first and second process steps may be selected based onthe material of the respective warpage control layer 1004 a, 1004 b. Insome embodiments, the first and second process steps may be selectedbased on the complexity of the pattern of the respective warpage controllayer 1004 a, 1004 b.

After the warpage control layer 306 is applied to the cured moldingcompound, the controlled semiconductor device packages may be separatedfrom other packages and assembled into another device (e.g.,semiconductor package, POP stack, processor, etc.). The controlledsemiconductor device package may be attached to the other device througha process such as a reflow process where the heat of the process maycause the controlled semiconductor device and/or the other device totend to warp. The warpage control layer 306 may control the warpage ofthe controlled semiconductor device, enabling the attachment between thecontrolled semiconductor device package and the other device with fewerfailures.

Some embodiments of the present disclosure may include a method offabricating a microelectronic device. The method may include positioninga first encapsulated microelectronic device over a second encapsulatedmicroelectronic device. The method may further include applying awarpage control structure on an encapsulant extending over a surface ofat least one of the first microelectronic device and the secondmicroelectronic device. The method may also include joining conductiveelements extending between the first microelectronic device and thesecond microelectronic device.

In some embodiments, a POP stack may be formed from semiconductordevices. FIG. 14 illustrates a method of assembling a POP stack 1400.One or more semiconductor devices (e.g., semiconductor packages, etc.)may be stacked on a base semiconductor device package in act 1402. Thebase semiconductor device package may be formed on a strip with multiplebase semiconductor devices. A POP stack may be formed on each basesemiconductor device package in the strip.

After the one or more semiconductor device packages are stacked on thebase semiconductor device package in act 1402, the warpage layer may beapplied to the top most semiconductor device package (e.g., top of thePOP stack) in act 1404. The warpage control layer may be applied throughany of the processes described above such as photolithography, etching(e.g., wet etching, dry etching, photo etching, atomic layer etching,etc.), deposition (e.g., chemical vapor deposition, atomic layerdeposition, physical vapor deposition etc.), electroplating, etc.Further, the warpage control layer may comprise a preformed structure,and adhered to the semiconductor device package.

After the stack is formed and the warpage layer is applied to the top ofthe stack, the individual semiconductor devices may be secured to oneanother through a reflow process in act 1406. The reflow process, suchas a reflow process described above, may involve high temperatures thatmay cause warpage in the semiconductor device packages. The individualsemiconductor devices may interact with one another under the heat ofthe reflow process such that all of the individual semiconductor devicepackages in the POP stack warp in a similar way resulting in a warpageof the POP stack. The warpage control layer applied to the top of thePOP stack may control the warpage of the entire POP stack during thereflow process.

In some embodiments, the individual semiconductor devices in the POPstack may also include individual warpage control layers. In otherembodiments, the individual semiconductor devices in the POP stack maynot include individual warpage control layers, such that the warpagecontrol layer on the top of the POP stack may be the only warpagecontrol layer present in the POP stack.

Embodiments of the present disclosure may result in semiconductordevices with controlled warpage during the process of forming thesemiconductor devices. Controlled warpage of the semiconductor devicesmay result better connections between multiple semiconductor devices.Better connection may result in fewer failures in electronic devices,chips, and/or semiconductor devices resulting from uncontrolled warpage.Controlled warpage of the semiconductor devices may also enable asemiconductor device to compensate for uncontrolled warpage of anothercomponent or device to which the semiconductor device is to be coupled.

The embodiments of the disclosure described above and illustrated in theaccompanying drawings do not limit the scope of the disclosure, which isencompassed by the scope of the appended claims and their legalequivalents. Any equivalent embodiments are within the scope of thisdisclosure. Indeed, various modifications of the disclosure, in additionto those shown and described herein, such as alternative usefulcombinations of the elements described, will become apparent to thoseskilled in the art from the description. Such modifications andembodiments also fall within the scope of the appended claims andequivalents.

What is claimed is:
 1. A microelectronic device package, comprising: asubstrate; one or more microelectronic devices positioned over thesubstrate; an encapsulant material surrounding and extending over theone or more microelectronic devices; and at least one warpage controllayer positioned over and secured to a surface of the encapsulantmaterial, the at least one warpage control layer having a first regionhaving a first thickness and a second region having a second thicknessgreater than the first thickness of the first region.
 2. Themicroelectronic device package of claim 1, further comprising conductiveelements comprising a solder material protruding from the substrate, andwherein the at least one warpage control layer is configured to controlwarpage of the microelectronic device package during reflow of theconductive elements.
 3. The microelectronic device package of claim 1,wherein the at least one warpage control layer is configured to reducewarpage of the microelectronic device package in at least one regionthereof.
 4. The microelectronic device package of claim 1, wherein theat least one warpage control layer is configured to increase warpage ofthe microelectronic device package in at least one region thereof. 5.The microelectronic device package of claim 1, wherein the at least onewarpage control layer comprises at least two exterior surfaces above andparallel to the surface of the encapsulant material.
 6. Themicroelectronic device package of claim 1, wherein the at least onewarpage control layer comprises one or more ridges.
 7. Themicroelectronic device package of claim 1, wherein the at least onewarpage control layer comprises a material having a thickness of up toabout 20 mm.
 8. The microelectronic device package of claim 1, whereinthe at least one warpage control layer comprises a first material and asecond, different material.
 9. The microelectronic device package ofclaim 8, wherein the first material has a first coefficient of thermalexpansion and the second, different material has a second, differentcoefficient of thermal expansion.
 10. The microelectronic device packageof claim 9, wherein the first coefficient of thermal expansion is largerthan an average coefficient of thermal expansion of the microelectronicdevice package without the at least one warpage control layer and thesecond, different coefficient of thermal expansion is smaller than theaverage coefficient of thermal expansion of the microelectronic devicepackage without the at least one warpage control layer.
 11. A controlledwarpage microelectronic device package, comprising: at least onemicroelectronic device substantially encapsulated in a molding material;a warpage control structure secured to the molding material andcomprising: a first material, wherein a first portion of the firstmaterial has a first thickness and at least a second portion of thefirst material has a second thickness; wherein the first portion ispositioned over a first region of the molding material and the secondportion is positioned over a second region of the molding material. 12.The controlled warpage microelectronic device package of claim 11,wherein the warpage control structure further comprises a second,different material.
 13. The controlled warpage microelectronic devicepackage of claim 12, wherein the first material has a first coefficientof thermal expansion that is larger than a second coefficient of thermalexpansion of the second, different material.
 14. The controlled warpagemicroelectronic device package of claim 12, wherein the second thicknessof the second portion of the first material is less than the firstthickness of the first portion of the first material and the second,different material is positioned over the second portion of the firstmaterial.
 15. The controlled warpage microelectronic device package ofclaim 12, wherein the second, different material is positioned laterallyadjacent to the first material.
 16. A method of forming a device packagecomprising: positioning at least one die on a substrate; encapsulatingthe die in a molding compound extending to a surface of the substrate;curing the molding compound; and applying at least two warpage controlstructures over the molding compound, at least one of the at least twowarpage control structures having a first region having a firstthickness and a second region having a second thickness greater than thefirst thickness of the first region.
 17. The method of claim 16, whereinapplying the at least two warpage control structures further comprisesforming one or more ridges of at least one warpage control material overthe molding compound.
 18. The method of claim 16, further comprisingdesigning a cross-sectional profile of the at least two warpage controlstructures to match a warpage of an adjoining semiconductor device. 19.The method of claim 18, wherein designing the at least two warpagecontrol structures comprises simulating warpage of the device packageresponsive to a heat cycle of a solder reflow process.
 20. The method ofclaim 16, wherein applying the at least two warpage control structuresfurther comprises applying a first warpage control material and applyinga second, different, warpage control layer.
 21. A method of fabricatinga microelectronic device comprising: positioning a first encapsulatedmicroelectronic device over a second encapsulated microelectronicdevice; applying a warpage control structure on a surface of anencapsulant extending over at least one of the first encapsulatedmicroelectronic device and the second encapsulated microelectronicdevice, the warpage control structure having a first region with a firstthickness and a second region with a second thickness greater than thefirst thickness in the first region; and joining conductive elementsextending between the first encapsulated microelectronic device and thesecond encapsulated microelectronic device.
 22. The method of claim 21,wherein joining the conductive elements comprises reflowing solderbetween the first encapsulated microelectronic device and the secondencapsulated microelectronic device.
 23. The method of claim 21, furthercomprising applying the warpage control structure to a surface of thesecond encapsulated microelectronic device.
 24. The method of claim 23,further comprising selecting at least one property of the warpagecontrol structure to generate a second warpage of the secondencapsulated microelectronic device that matches a first warpage of thefirst encapsulated microelectronic device.
 25. A microelectronic devicepackage, comprising: one or more microelectronic devices connected to asubstrate; an encapsulant material extending around and over the one ormore microelectronic devices and abutting a surface of the substrate;and at least two warpage control structures secured to a surface of theencapsulant material and extending over the one or more microelectronicdevices, each of the at least two warpage control structures contactingthe encapsulant material.
 26. The microelectronic device package ofclaim 25, wherein at least one of the at least two warpage controlstructures has a first region having a first thickness and a secondregion having a second thickness greater than the first thickness of thefirst region.